Research on 1,2 -dithiolium derivatives II. Oxidation of arylhydrazones of dithiomesoxalic acid diarylamides to 1,2-dithiolium derivatives

Arylazo derivatives of 3,5-diamino-1,2-dithiolium bromides were obtained by oxidation of arylhydrazones of dithiomesoxalic acid diamides with bromine in chloroform; the nonquaternized amino group of the products reacts with aryl iso(thio)cyanates to give the corresponding ureas and thioureas, regardless of the conditions.See [1] for communication I.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 909–911, July, 1978.     

6,7-diaza-dithiafulvalenes and 5-aza-8a-azonia-dithiafulvalenes

3-Dimethylamino- and 3,5-Bis-dimethylamino-pyrazoles react with 1,2- and 1,3-dithiolium salts to form 6,7-diaza-dithiafulvalenes and 5-aza-8a-azonia-dithiafulvalenes, a new type of heterofulvalenes.     

The preparation of bis(isopropoxy)thiolato complexes of titanium(IV) and their Lewis base adducts

Reactions of titanium tetraisopropoxide with various thiols are reported. In the absence of other donating atoms, appreciable product formation is observed only with 1,2-dithiols. Monothiols and 1,3-dithiols react in the presence of nitrogen donors and 2-aminobenzene thiol reacts spontaneously. Complexes with 1,2-dithiols and bidentate nitrogen donors adopt the cis configuration in solution. Compounds were characterized by NMR, IR, molecular weights (in solution) and elemental analysis.     

Structure electronique de derives sulfures—IV: Etude theorique de la reduction electrochimique du cation dithiolylium-1,2

The cathodic reduction of 1,2-dithiolium cation has been studied by the CNDO/2 method, applied for open shell problems in ”restricted” and “unrestricted” formalisms. The stability of 1,2-dithiolium radical is confirmed as well as the tendency of 1,2-dithiolium anion to form the 1,3-dithioketonate anion by ring opening.     

Synthesis of 3-imino and 3-ylideno derivatives of 4-fluoro-5-polyfluoroalkyl-1,2-dithiolenes

Reactions of 4-fluoro-5-polyfluoroalkyl-1,2-dithiol-3-thiones with hydroxylamine and hydrazines occur with replacement of the thiocarbonyl by imino group affording oximes and hydrazones respectively. N-Alkyl-and N-aryl-3-imino-1,2-dithiolenes formed in reactions of 3-chlorothio-1,2-dithiolium salts with primary alkyl-or arylamines. 3-Chlorothio-1,2-dithiolium salts react with compounds possessing an active methylene group yielding 3-ylideno derivatives of 1,2-dithiolenes.     

Structure electronique de derives sulfures—III: Dithiole-1,2 thione-3 et mercapto-3 dithiolylium-1,2

CNDO/2 calculations with modified parametrization for d orbitals have been performed on 1,2-dithiol-3-thione and the 3-mercapto 1,2-dithiolium cation. The electronic structures are discussed and compared with some experimental data. The modification of electronic spectra of 1,2-dithiol-3-thione by protonation is interpreted theoretically.     

Addition of 1,2- and 1,3-Dithiols to 2-alkoxypropenals - a New Method for the Production of Substituted Dithiacycloalkanes

The reaction of 2-alkoxypropenals with ethane-1,2-dithiols and propane-1,3-dithiols under various conditions was studied by ¹H NMR and chromato-mass spectrometry. Under kinetically controlled conditions at 20° in the absence of catalysts the addition of dithiols takes place according to the Markovnikov rule. The primary adducts are unstable and are quickly converted into the corresponding substituted 1,4-dithiacycloheptane or 1,4-dithiane. The latter in turn can be converted under the reaction conditions or at high temperature into a thiolane derivative. The reaction of 2-ethoxypropenal with a twofold excess of ethane-1,2-dithiol at 60°C in the presence of p-toluenesulfonic acid leads to 2-methyl-2,2'-bi(dithiolane)     

2-(2-furyl)imidazo[1,2-a]pyrimidine synthesis and electrophilic substitution reactions

The synthesis of 2-(2-furyl)imidazo[1,2-a]pyrimidine has been carried out. Azocoupling, nitrosation, and bromination by 1 mole of bromine occur at position 3 of the bicycle. Reaction with 2 mol of bromine gives the 3,5‰-disubstituted derivative. Bromination using 1 mol of bromine in 40% hydrobromic acid and sulfonation occur initially at the 5‰ position of the furyl group. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 565–570, April, 2006.     

Insight into Out-of-Layer Fluctuations in the Smectic A Stability of 3,5-Diarylisoxazole Liquid Crystals

Polar-terminated 3,5-diarylisoxazole liquid crystals (ILCs) were synthetized and characterized. ILCs are composed by rigid core 3,5-diarylisoxazol, alkyl chain and polar-terminated flexible spacer. Hydroxyl-, ketal- and 1,2-diol-terminated ILCs rendered smectic C and A mesophase, while bromine-terminated ILCs showed smectic A and B mesophase, for monosubstituted and linear ILCs. For branched alkyl chain monotropic SmA was detected and for disubstituted ILCs no mesophase was detected. Out-of-layer fluctuations (OLFs) are discussed based on X-ray diffraction date and textures. The OLFs are dependent on the bromine atom hardness, hydrogen bonding through collective actions and conformational effects at the interface between layers. Smectic translational order parameter (TOP) Σ was also obtained for orientated bromine- and hydroxyl-terminated ILCs and related it with OLFs. For 1,2-diol-terminated ILCs two SmC sublayers were founded, probably related to the intramolecular hydrogen bond favoring the 5-membered and 6-membered formation.     

Cyclische Ester der Methanarsinsäure

Zusammenfassung In benzol. Lösung entstehen bei Anwesenheit einer Base fünfgliedrige cyclische Ester der Methanarsinsäure durch Umsetzung von 1,2-Diolen und 1,2-Dithiolen mit Methylarsendihalogenid.

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1.2-diols and 1.2-dithiols react with methylarsenicdiiodide in benzene solution and accordance of triethylamine as a base yielding cyclic esters.

     

General access to a novel class of silyl heterocycles

2-Trimethylsilyl-substituted five-membered heterocycles can be accessed through the reaction of bromo(methoxy)methyltrimethylsilane with 1,2-dithiols, 1,2-mercapto alcohols, 1,2-mercapto amines, and 1,2-hydroxy amines, leading to the formation of several 2-silylated 1,3-dithiolanes,-oxathiolanes,-thiazolidines, and-oxazolidines. Dedicated to Prof. Edmunds Lukevics on the occasion of his 70th birthday __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1838–1844, December, 2006.     

Structure electronique de derives sulfures—II : Spectres electroniques du cation dithiolylium-1,2 et de ses derives de monosubstitution

The electronic spectra of the 1,2-dithiolium cation and of four monosubstituted derivatives have been studied by CNDO/S method, extended to the third period with inclusion of 3d orbitals. Calculated effects of a substitution by a methyl or a phenyl group are in good agreement with experimental data.     

3,4-Dihydro-2-phenyl-2H-pyrano[2,3-b]pyridines. Novel aza analogs of flavans

Complementary approaches to the synthesis of the title compounds 1 are described. Metallation of 3,5-di-bromo-2-methoxypyridine ( 5b ) by bromine/lithium exchange gave selectively the 3-lithio intermediate 6 which was trapped with substituted cinnamaldehydes 7 , providing allylic alcohols 8 in good yields. Methyl ether cleavage and concomitant cyclization occurred on exposure to concentrated hydrobromic acid in hot acetic acid. The resulting 2-phenyl-2H-pyrano[2,3-b]pyridines were hydrogenated over Raney nickel to the title compounds which had antiviral activity. Alternatively, 1 were synthesized by Heck reaction of appropriately substituted 3-halo-2-methoxypyridines ( 5 or 24 ) with vinyl carbinol 15 to furnish ketones 16 or 26 which, upon reduction of the carbonyl group, were cyclized directly to 1 .     

Offene und cyclische Methylstibonigsäureester. II

Esters of Methylstibonous Acid. II. The reaction of methyldibromstibine with sodium alcoholates and phenolates yield methyldialkoxi and methyldiphenoxistibines. Interchange reactions of the methyldiethoxistibine with thiols, 1,2-diols, 1,2-dithiols, and 2-mercapto-1-oles form dithioesters and cyclic esters of the methylstibonous acid in nearly quantitativ amount and high purity.     

Synthesis of poly dithioesters and cyclization to 1, 3-dithiolium (dithiafulvenium) salts

Piperidinium dithiobenzoate and piperidinium tetrathioterephthalate react with α-halo carbonyl compounds to give small molecules and polymers which, upon dehydrative cyclization with H₂SO₄, yield materials containing the 1,3-dithiolium ring. Maximum yields are obtained by use of phase-transfer techniques and the solvent system H₂O/CH₂Cl₂. The cyclized polymers are soluble in sulfuric acid, and films can be made from (CF₃)₂ CHOH solutions.     

REACTION OF (ORGANYLTHIO)CHLOROACETYLENES WITH ALIPHATIC 1,2-DITHIOLS: A ROUTE TO FUNCTIONALIZED 1,3-DITHIOLANES

(Organylthio)chloroacetylenes react with aliphatic 1,2-dithiols in dimethyl sulfoxide at 20–25°C in the presence of a two-fold molar excess of alkali to form 2-[(alkylthio)methyliden]-1,3-dithiolanes in up to 66% yield.     

Synthesis and antioxidant activity of sterically hindered bis-pyrocatechol thioethers

A reaction of 3,5-di-tert-butyl-o-benzoquinone with 1,2- and 1,6-dithiols was used to obtain the corresponding bis-pyrocatechol thioethers; a comparative evaluation of their antioxidant activity was carried out. The synthesized thioethers, 2-(4,6-di-tert-butyl-2,3-dihydroxyphenylsulfanyl)acetic acid, and 3,5-di-tert-butylpyrocatechol were studied in the reaction with diphenylpicrylhydrazyl radical. The influence of these compounds on the autooxidation process of oleic (cis-octadec-9-enoic) acid was studied. The antioxidant activity of bis-pyrocatechol thioethers was manifested in the reaction with diphenylpicrylhydrazyl radical in the process of autooxidation of oleic acid, which was confirmed by the experimental EC₅₀ values, the data on the number of transformed molecules of stable radical ( ⁿ DPPH), and the relative content of oleic acid hydroperoxides. Bis-pyrocatechol thioethers were found to exhibit the inhibitory activity in the course of oxidation of glutathione induced by 2,2’-azobis(2-amidinopropane) dihydrochloride.     

Chlorination and oxidation of 4-fluoro-5-tetrafluoroethyl-1,2-dithiole-3-thione

Chlorination of 4-fluoro-5-(1,1,2,2-tetrafluoroethyl)-1,2-dithiole-3-thione with an equimolar amount of chlorine or sulfuryl chloride gives 3-chlorosulfanyl-4-fluoro-5-(1,1,2,2-tetrafluoroethyl)-1,2-dithiolium chloride. The reaction of the title compound with excess chlorinating agent leads to 3,3,4,5-tetrachloro-4-fluoro-5-(1,1,2,2-tetrafluoroethyl)-1,2-dithiolane. By oxidation and oxidative imination of 4-fluoro-5-(1,1,2,2-tetrafluoroethyl)-1,2-dithiole-3-thione, the corresponding S-oxide and sulfimide were obtained, respectively.     

Substituent effects of 1,2-dithiole groups on the electrochemical oxidation of some ferrocenyl-1,2-dithiole compounds

New ferrocenyl compounds substituted by sulfur containing groups were synthesized leading to ferrocenyl-3H-1,2-dithiole-3-thiones and related compounds. The substituent of the ferrocene was a [3-thioxo-3H-1,2-dithiol]-4 or 5-yl, a [3-oxo-3H-1,2-dithiol]-4 or 5- yl or a [3-methylsulfanyl-3H-1,2-dithiolium]-4 or 5-yl cation group. Their anodic behavior was studied by cyclic voltammetry at a Pt electrode in aprotic solvent. All synthesized ferrocenes exhibited a one-electron reversible oxidation leading to the corresponding ferricinium cation. At low potential scan, the irreversible oxidation of 5-ferrocenyl-3H-1,2-dithiole-3-thione was observed and attributed to a dimerization involving the dithiolethione group. Redox potential of the reversible oxidation allowed the determination of the electronic effect of the 1,2-dithiole groups. The Hammett σ_p constants of the dithiole substituents were obtained from linear correlation between oxidation potentials and electronic effects. The results showed that the [3-thioxo-3H-1,2-dithiol]-5-yl and the [3-methylsulfanyl-3H-1,2-dithiolium]-5-yl cation groups were strong inductive electron withdrawing substituents characterized by σ_p values of 0.55 and 0.97, respectively.     

Synthesis,thermal stability and mass spectra of 2-trihalomethyl-1,3,5-dithiazin-4-ones and their 2,3-dihydro derivatives

A method has been proposed for the synthesis of 2-trihalomethyl-1, 3,5-dithiazines based on the reaction of 1 1, -dithiols with 1, 1-dichloro- and I -chloroalkyl isocyanates. The thermal stability and mass spectra of these compounds were studied.Institute of Organic Chemistry, National Academy of Sciences of Ukraine, 252660 Kiev, Ukraine. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp, 996–1000, July, 1995. Original article submitted February 21, 1995.